enum BE
{
    b0 = 1<<0,
    b1 = 1<<1,
    b2 = 1<<2,
    b3 = 1<<3,
    b4 = 1<<4,
}

class BBB
{
    public BE be;
}

public void foo(IMongoCollection coll)
{
    coll.InsertMany(new []
    {
        new BBB{be=BE.b1},
        new BBB{be=BE.b2},
        new BBB{be=BE.b3},
        new BBB{be=BE.b4},
    });

    var mask = BE.b1 | BE.b3;

    var qb1 = coll.FindSync(b => (b.be & mask) != 0); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
    var qb2 = coll.FindSync(b => (b.be & mask) == 0); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
    var qb3 = coll.FindSync(b => (b.be & mask) != mask); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
    var qb4 = coll.FindSync(b => (b.be & mask) == mask); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'

    var q1 = coll.AsQueryable().Where(b => (b.be & mask) != 0).ToList(); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
    var q2 = coll.AsQueryable().Where(b => (b.be & mask) == 0).ToList(); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
    var q3 = coll.AsQueryable().Where(b => (b.be & mask) != mask).ToList(); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
    var q4 = coll.AsQueryable().Where(b => (b.be & mask) == mask).ToList(); //System.InvalidOperationException: 'Convert(Convert((Convert({document}{be}) & 10))) is not supported.'
}